How does AV reduce negative campaigning?

While politicians can get elected with a minority under FPTP, AV forces candidates to achieve more than 50% of the vote. Instead of relying on tactical voting and splitting voters, AV encourages candidates to build support by appealing to a broad range of voters.

Extremist parties are unlikely to get elected, though their candidates may have larger number of first preference votes, and candidates engaged in negative campaigning are likely to cut themselves off from ordinary voters.